This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:
3GPP third generation partnership project
AP access point
BW bandwidth
CC component carrier
CDM code division multiplexing
CRC cyclic redundancy check
DL downlink (eNB towards UE)
DoS denial of service
eNB E-UTRAN Node B (evolved Node B)
EPC evolved packet core
E-UTRAN evolved UTRAN (LTE)
HARQ hybrid automatic repeat request
HFC hybrid fiber coaxial
HSPA high speed packet access
IMT-A international mobile telephony-advanced
ITU international telecommunication union
ITU-R ITU radiocommunication sector
LTE long term evolution of UTRAN (E-UTRAN)
MAC medium access control (layer 2, L2)
MM/MME mobility management/mobility management entity
Node B base station
O&M operations and maintenance
OFDMA orthogonal frequency division multiple access
PDCP packet data convergence protocol
PDU protocol data unit
PHY physical (layer 1, L1)
RAT radio access technology
RLC radio link control
RLC-SN radio link control sequence number
RRC radio resource control
RRM radio resource management
SC-FDMA single carrier, frequency division multiple access
S-GW serving gateway
SIM subscriber identity module
SRB signaling radio bearer
STA station
TCP transmission control protocol
UE user equipment, such as a mobile station or mobile terminal
UL uplink (UE towards eNB)
UTRAN universal terrestrial radio access network
WLAN wireless local area network
The specification of a communication system known as evolved UTRAN (E-UTRAN, also referred to as UTRAN-LTE or as E-UTRA) is currently nearing completion within the 3GPP. As specified the DL access technique is OFDMA, and the UL access technique is SC-FDMA.
One specification of interest is 3GPP TS 36.300, V8.12.0 (2010-04), “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E UTRA) and Evolved Universal Terrestrial Access Network (E UTRAN); Overall description; Stage 2 (Release 8),” incorporated by reference herein in its entirety. This system may be referred to for convenience as LTE Rel-8 (which also contains 3G HSPA and its improvements). In general, the set of specifications given generally as 3GPP TS 36.xyz (e.g., 36.211, 36.311, 36.312, etc.) may be seen as describing the Release 8 LTE system. More recently, Release 9 versions of at least some of these specifications have been published including 3GPP TS 36.300, V9.9.0 (2011-12), incorporated by reference herein in its entirety, and Release 10 versions of at least some of these specifications have been published including 3GPP TS 36.300, V10.6.0 (2011-12), incorporated by reference herein in its entirety. Even more recently, Release 11 versions of at least some of these specifications have been published including 3GPP TS 36.300, V11.0.0 (2011-12), incorporated by reference herein in its entirety.
FIG. 1 reproduces FIG. 4-1 of 3GPP TS 36.300, and shows the overall architecture of the E-UTRAN system. The E-UTRAN system includes eNBs, providing the E-UTRA user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UE (not shown). The eNBs are interconnected with each other by means of an X2 interface. The eNBs are also connected by means of an S1 interface to an EPC, more specifically to a MME (Mobility Management Entity) by means of a S1 MME interface and to a Serving Gateway (SGW) by means of a S1 interface. The S1 interface supports a many-to-many relationship between MMEs/S-GW and eNBs.
The eNB hosts the following functions:                functions for RRM: Radio Bearer Control, Radio Admission Control, Connection Mobility Control, Dynamic allocation of resources to UEs in both UL and DL (scheduling);        IP header compression and encryption of the user data stream;        selection of a MME at UE attachment;        routing of User Plane data towards the Serving Gateway;        scheduling and transmission of paging messages (originated from the MME);        scheduling and transmission of broadcast information (originated from the MME or O&M); and        a measurement and measurement reporting configuration for mobility and scheduling.        
Of particular interest herein are the further releases of 3GPP LTE (e.g., LTE Rel-10) targeted towards future IMT-A systems, referred to herein for convenience simply as LTE-Advanced (LTE-A). Reference in this regard may be made to 3GPP TR 36.913, V8.0.1 (2009 03), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Requirements for Further Advancements for E UTRA (LTE-Advanced) (Release 8), incorporated by reference herein in its entirety. A goal of LTE-A is to provide significantly enhanced services by means of higher data rates and lower latency with reduced cost. LTE-A is directed toward extending and optimizing the 3GPP LTE Rel-8 radio access technologies to provide higher data rates at very low cost. LTE-A will most likely be part of LTE Rel-10. LTE-A will be a more optimized radio system fulfilling the ITU-R requirements for IMT-A while maintaining backward compatibility with LTE Rel-8. Reference is further made to a Release 9 version of 3GPP TR 36.913, V9.0.0 (2009-12), incorporated by reference herein in its entirety. Reference is also made to a Release 10 version of 3GPP TR 36.913, V10.0.0 (2011-06), incorporated by reference herein in its entirety.
As is specified in 3GPP TR 36.913, LTE-A should operate in spectrum allocations of different sizes, including wider spectrum allocations than those of Rel-8 LTE (e.g., up to 100 MHz) to achieve the peak data rate of 100 Mbit/s for high mobility and 1 Gbit/s for low mobility. It has been agreed that carrier aggregation is to be considered for LTE-A in order to support bandwidths larger than 20 MHz. Carrier aggregation, where two or more component carriers (CCs) are aggregated, is considered for LTE-A in order to support transmission bandwidths larger than 20 MHz. The carrier aggregation could be contiguous or non-contiguous. This technique, as a bandwidth extension, can provide significant gains in terms of peak data rate and cell throughput as compared to non-aggregated operation as in LTE Rel-8.
A terminal may simultaneously receive one or multiple component carriers depending on its capabilities. A LTE-A terminal with reception capability beyond 20 MHz can simultaneously receive transmissions on multiple component carriers. A LTE Rel-8 terminal can receive transmissions on a single component carrier only, provided that the structure of the component carrier follows the Rel-8 specifications. Moreover, it is required that LTE-A should be backwards compatible with Rel-8 LTE in the sense that a Rel-8 LTE terminal should be operable in the LTE-A system, and that a LTE-A terminal should be operable in a Rel-8 LTE system.
FIG. 2 shows an example of the carrier aggregation, where M Rel-8 component carriers are combined together to form M×Rel-8 BW (e.g., 5×20 MHz=100 MHz, given that M=5). Rel-8 terminals receive/transmit on one component carrier, whereas LTE-A terminals may receive/transmit on multiple component carriers simultaneously to achieve higher (wider) bandwidths.
With further regard to carrier aggregation, what is implied is that one eNB can effectively contain more than one cell on more than one CC (frequency carrier), and the eNB can utilize one (as in E-UTRAN Rel-8) or more cells (in an aggregated manner) when assigning resources and scheduling the UE.
The amount of wireless data might increase 100 fold in 5 years. Already smart phones are facing a lack of capacity in their networks. All methods to help with this are welcome. One approach is to use carrier aggregation over a plurality of radio access technologies (RATs). For example, one carrier may be in an unlicensed frequency (e.g., WLAN). This carrier may then be used in cooperation with an LTE carrier, to transmit data. This requires that both devices, for example, a user equipment (UE) and a LTE access point (AP), have at least two radio interfaces, e.g., one for LTE and one for WiFi (IEEE 802.11).
As more devices move to use inter-RAT carrier aggregation, security for the various RATs will be needed. Currently, different RATs (e.g., LTE and WiFi) have their own security solutions, independent of each other. Meeting the needs for these various security solutions when using inter-RAT CA can incur a heavy configuration and processing burden on both the receiver and transmitter.
What is needed is a technique to provide security for inter-RAT carrier aggregation which is easy for the network operator to configure and does not overly burden the receiver and transmitter.